Sorry for this long post

I need to ask for advice from all the experts. My MCS has Nology wires, Iridium Plugs, Screamin Demon coil, Dinan Throttle Body, Cold Air Intake, 15% pulley, Dinan Stage 4 software, Ultrik Header and high flow cat and the Borla Cat Back System. I also have the Dinan Stage 3 suspension kit (that doesn't apply to this thread but I paid for it so I am going to mention it )

My problem is that the check engine light comes on about every 30 miles throwing the fault code P2270 - O2 Senso Signal stuck lean - bank 1 sensor 2. Mini Mania has already replaced the header and cat under warranty to no avail.

Reading the other posts and forums here and elsewhere, everyone seems to believe that with a 15% pulley the engine runs fine without upgraded injectors. I am not in the position right now to spend a lot of money. So my question is how should I approach this problem. Should I:

1. replace the O2 sensor
2. go with upgraded JCW injectors - or others
3. upgrade to the stage 5 Dinan software - which Dinan recommends with
their pulley
4. Go with the Dinan boost kit except for the Pulley - the most expensive option

Dinan claims:
The increase in boost pressure is accomplished in typical fashion, employing a smaller supercharger pulley. Unfortunately, extensive testing revealed that the stock fuel delivery system simply can’t keep up as boost and rpm increase. In order to address the lean condition at higher rpm, Dinan has developed fuel pressure regulators designed to ensure that adequate fuel is available in order to take full advantage of the additional boost pressure for maximum power output and reliability.

Lots of conflicting advice ...... Answers??????

Thanks, J. R.